How to Make Nanoparticles?

Delft, October 29th 

Previously published on Azonano Magazine

How Did You Invent Spark the Ablation Technique?

When I was a PhD student, my supervisor told me to make small particles, but he didn’t tell me how. We were only interested in the basic properties of these particles, so he asked me to just do it somehow. At that time you couldn’t make small particles by exploding wires, these particles were called just small particles or clusters. Nanoparticles were not well known.

The first thing I tried was exploding wires, and it worked out somehow. It was not practical, because it didn’t allow you have a continuous output for an experiment, and if you want to study basic properties of particles you really need a continuous source. Especially if you want to study them suspended in a noble gas.

To suspend these particles in a noble gas they need to be suspended in nothing, with this method they were falling down in a vacuum so you could have them only for nanoseconds. So I took a big capacitor with an electrical energy that released energy in a wire.

One day there was a bad contact in the machine, the wires were not properly connected and that meant when I turned on the high voltage there were sparks everywhere. Attached to the machine I had a nanoparticle detector, which as the name suggests, detected nanoparticles. I was surprised, because they were not coming from exploding wires, but from the sparks produced by mistake.

Immediately, I became curious about this result and I created a small device to reproduce the same process. The machine was nothing more than a little plastic tube with two electrodes at a fixed distance, then I started to perform experiments applying a high-voltage source to produce sparks.

From the beginning of my tests, I noticed unique benefits using spark ablation that I couldn’t find in other techniques. For instance, with exploding wires (a method still widely used) you can’t produce pure carbon nanoparticles, because the evaporating temperature can’t be reached and the wires will release waste material together with the particles.

 With the spark ablation technology, you can easily have a continuous output to generate carbon nanoparticles without wasting material.

What Was the Connection Between the Research and Starting the Company?

As a researcher you have a lot of good ideas, but with most of them you can’t make any profit. Indeed, from the invention of spark it took many decades to found a company.

When in 2014 Aaike (now CEO of VSPARTICLE) and I set together, we thought about commercializing this way of making nanoparticles. Nanotechnology was growing and now there is an increasing need for making nanoparticles, especially for applications like carbon filters and simulating carbon exhaust.

Since the reach for nanotechnology is broad, nanoparticles are now the building blocks of the future.

What Did You Want to Enable People to Do?

At the beginning the idea was quite general, to produce devices and applications, for example.

We had the feeling that we had to capitalize on the timing and be the first ones to enable generation of nanomaterials in an easy, safe and reproducible way.

Aaike worked on this project during his Master thesis, so he realized that this spark ablation device is a very useful source that has incredible benefits: you can produce clean, controllable nanoparticles of any (semi)conductive material.

Which Were the Main Challenges You Had to Face to Start the Company?

We can easily state that sustainability is a big challenge for research, because you can waste a large amount of material while performing your experiment.

Indeed, the amount of material you use with spark ablation is the same as what you convert into nanoparticles, this is a zero waste technique. You can start with a small piece of radioactive gold (very expensive) and convert 100% of material in nanoparticles.